While not a belly button, I had two cartilage ear piercings that attempted to reject. I had them for 5 years, and every 6 months or so, they'd get really upset and bleed. Constant crusties, and they swelled up pretty good all around the piercing. I couldn't move the rings at all, other than turning them, because the swelling hurt so much.
There are a lot of things I could have done, or that I could have been told, about having those piercings. To get one at a time, so I could sleep on one side and keep the other without pressure. To keep my hair back and away from them at all times. To not get them when I'm working a job where I have to wear a headset (I was working in a call centre).
I tried the salt, the oils and everything... I did a lot of research. By the end of 5 years, I decided that they would never heal, and I discarded them. Very little scar tissue, so that's good. They healed up perfectly fine with the rings out.
However, I wanted to say this: Using things like polysporin, or something oil based, is not recommended because it doesn't allow the wound to breathe. It's a very particular kind of thing you're trying to do, and suffocating your skin around the piercing may cause it to stop healing, reject entirely, or other nasty things.
Using salts (such as epsom salts or seasalt) can be very beneficial. I didn't find that it helped me, but there were a lot of people that I read about that found it amazing, so you can give that a try.
Otherwise, belly button piercings are, from what I've seen, just as bad as any surface piercing for being rejected. I've heard of them being rejected only to one side, so you end up with a piercing somewhere near your hipbone, and some just are rejected out. That's where the skin becomes smaller and smaller... till the piercing itself comes out.
Specifically, crusties are a fluid that our bodies use, created by the Lymph node, in order to flush out foreign objects- namely, the piece of metal you've shoved in there. They're normal, and natural for your body to be producing.
I'd say, leave the piercing in for a bit, try to be very careful of it (if it keeps wrenching or moving, perhaps put a bandage over it to keep it from doing so). Pulling or moving it when it's not healed, and discovering it bleeding, is a sure sign that whatever healing had been done was wrecked by the movement. It's a very delicate process!
And... some people heal differently than others. Some people take ages, some take days. Some don't heal up at all- such as myself.
I wish you luck!
